1. Field of the Invention
The present invention relates to a differential apparatus for a vehicle, and more particularly relates to the differential apparatus for the vehicle having a differential restricting mechanism to restrict a differential mechanism.
2. Description of the Related Art
It is well known for this kind of the differential apparatus for the vehicle as shown in a prior art as disclosed in a document of a Tokkai 2007-138983 disclosing a differential apparatus for a vehicle having a differential restricting mechanism restricting any differential of a differential mechanism by combining one of a pair of output shafts and an input shaft.
This conventional differential apparatus for the vehicle as the prior art mainly constitutes of a housing rotated with the input shaft as a input member, the differential mechanism distributing differentially rotational force from the housing, a main clutch restricting the differential of the differential mechanism, and a driving mechanism driving the main clutch.
The housing includes a front housing opening to one direction with a bottom and an annular rear housing mounted on the opening portion of the front housing, and is connected to the input shaft.
The differential mechanism includes a ring gear as the pair of output gears connecting the pair of output shafts respectively, a sun gear, a plurality of planetary gears as the input gear intermeshing with the ring gear and the sun gear, and a carrier supporting the plural planetary gears, and is accommodated in the housing. The differential mechanism is constructed to distribute differentially rotational force to the pair of output shafts.
The clutch includes outer clutch plates and inner clutch plates, and is disposed between an inner peripheral surface of the front housing and an outer peripheral surface of the ring gear. And the outer clutch plates and the inner clutch plates are frictionally engaged each other to connect the input shaft and the one output shaft of the pair of output shafts to restrict the differential of the differential mechanism. The outer clutch plates intermesh in spline with an inner peripheral surface of the front housing and the inner clutch plates intermesh in spline with an outer peripheral surface of the ring gear respectively and alternatively.
The driving mechanism includes an electromagnetic clutch, a pilot clutch driven by receiving the electromagnetic force of the electromagnetic clutch, a cam transforming rotational force from the housing to pressing force to the main clutch by the driving of the pilot clutch. The driving mechanism is disposed at a periphery of the pair of output shafts and accommodated in the housing. The driving mechanism is constructed to exert the pressing force from an output member of the cam to an output transmitting member including an annular cylindrical portion and a bottom portion, and then to the main clutch from the output transmitting member to engage frictionally the outer clutch plates and the inner clutch plates.
Upon the construction of the prior differential apparatus for the vehicle, when driving force from the engine of the vehicle is input to the housing, thereby to rotate the housing around a rotational axis. According to the rotation of the housing, the rotational force is transmitted to the plural planetary gears through the carrier, then to the ring gear and the sun gear through the plural planetary gears. Because the ring gear and the sun gear are connected to output shafts respectively, the driving force from the engine is differentially distributed according to a driving stage of the vehicle to be transmitted to the right and left output shafts.
In this case, when the electromagnetic clutch is energized, the electromagnetic force of the electromagnetic clutch drives the pilot clutch. Then, when the rotational force from the housing is received at the cam in a state of driving the pilot clutch, the rotational force is transformed to the pressing force by the cam so that the pressing force is exerted to the main clutch from the output member through the output transmitting member. Thereby, the pressing force makes the outer clutch plates and the inner clutch plates of the main clutch approach each other to engage them fictionally so that the housing and the ring gear, that is to say the input shaft and output shaft related to the ring gear are connected under the condition to be able to transmit the torque. Thereby, the differential of the differential mechanism is restricted.
However, in the prior art of the conventional differential device for the vehicle disclosed in the patent document, because the differential restricting force of the differential mechanism obtained by the clutch is generated between the housing and the ring gear, the restricting force is not obtained efficiently.
And also, in the prior art of the conventional differential device for the vehicle disclosed in the patent document, because the pressing force by the cam mechanism is transmitted from the opposite side of the carrier to the main clutch side, it needs an additional member like the output transmitting member penetrating the carrier to increase a number of parts and to make a whole apparatus complex, therefore to increase cost.